Composite reinforced perfluorosulfonic acid ion exchange membrane, preparation method and application thereof

Abstract

The application discloses a composite reinforced perfluorosulfonic acid ion exchange membrane and a preparation method and application thereof. The composite reinforced perfluorosulfonic acid ion exchange membrane is obtained by melt extrusion casting of perfluorosulfonic acid resin modified material onto the surface of a modified reinforcing mesh cloth and through calendering and compounding, and is obtained after sodiumization or hydrogenation; the perfluorosulfonic acid resin modified material comprises perfluorosulfonic acid fluorine type resin, sulfonated graphene and 2,5-diamino-p-benzenedisulfonic acid, and the mass ratio of the perfluorosulfonic acid fluorine type resin, the sulfonated graphene and the 2,5-diamino-p-benzenedisulfonic acid is 100:5-8:0.8-2. The composite reinforced perfluorosulfonic acid ion exchange membrane is applied to fuel cells, lithium batteries, vanadium batteries, chlor-alkali electrolysis, gas separation and photocatalysis.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ion exchange membrane, in particular to a composite reinforced perfluorosulfonic acid ion exchange membrane and its preparation method and application. BACKGROUND

[0002] Currently, there are two methods for forming perfluorosulfonic acid ion membranes: melt extrusion casting method and solution casting method. The solution casting method is usually to dissolve the perfluorosulfonic acid ion exchange resin in a solvent to form a solution, then deposit the solution on a certain substrate or pour the solution into a mold, and then volatilize the solvent to obtain a thin film. First, the volatilized solvent contains a large amount of toxic and harmful substances, which not only causes physical damage to the actual operators but also causes serious pollution to the environment, so it cannot meet the needs of green, healthy and environmental protection. Secondly, a long solvent volatilization process is needed after casting, which is low in production efficiency. Thirdly, the solution casting is difficult to control the uniformity of the thickness, and the thin film product also has the quality problem of easy discoloration. Therefore, the current PFSIEM industrial manufacturing technology is mainly extrusion casting method (i.e. the industrial manufacturing technology of Nafion membrane of American DuPont Company and Flemion membrane of Japanese Asahi Company), which includes gel extrusion casting forming and melt extrusion casting forming, and the gel extrusion casting forming still has the problem of plasticizer or solvent removal.

[0003] At the same time, the perfluorosulfonic acid ion exchange membrane will be affected by the use environment and the number of uses during the working process. For example, the ion exchange process will significantly increase the dimensional change rate of the perfluorosulfonic acid ion exchange membrane, or in the application working condition of dry-wet alternating change, a large wet stress will be formed inside the ion membrane, which will cause mechanical degradation of the ion membrane, and then may cause damage to the membrane structure in the long-term cyclic use working condition, ultimately affecting the service life of the ion membrane and the operation safety of the application device. SUMMARY

[0004] In view of the problems in the background art, the purpose of the present application is to provide a composite reinforced perfluorosulfonic acid ion exchange membrane and its preparation method, which uses sulfonated graphene and 2,5-diamino-p-benzenedisulfonic acid and other modifiers to modify the perfluorosulfonic acid fluororesin, which can ensure the stability of the perfluorosulfonic acid fluororesin during high-temperature processing, weaken the non-Newtonian fluid properties, and by controlling the addition amount of the modifier, the melt flow rate MFR can be stabilized between 3.5-4, the melt strength is appropriate, has good extrusion casting film forming property, is easy to be compounded with the reinforced mesh cloth after modification, has good interlayer adhesion, good appearance flatness, and the comprehensive mechanical and mechanical properties are improved. Compared with the traditional gel extrusion casting and solution casting forming, the present application does not use solvent, solving the pollution and toxicity problems in the production process.

[0005] In order to achieve the above-mentioned purpose, the application provides a composite reinforced perfluorosulfonic acid ion exchange membrane, which is obtained by melt extrusion and casting perfluorosulfonic acid resin modified material on the surface of a modified reinforcing mesh and through compression to obtain a perfluorosulfonic acid membrane, and then through sodium or hydrogen treatment; the perfluorosulfonic acid resin modified material comprises perfluorosulfonic acid fluorine type resin, sulfonated graphene and 2,5-diamino-p-benzenedisulfonic acid, and the mass ratio of the perfluorosulfonic acid fluorine type resin, the sulfonated graphene and the 2,5-diamino-p-benzenedisulfonic acid is 100:5-8:0.8-2.

[0006] Optionally, the modified reinforcing mesh is a reinforcing mesh after plasma treatment.

[0007] Optionally, the material of the reinforcing mesh is one of polytetrafluoroethylene, polyvinylidene fluoride and ethylene-tetrafluoroethylene copolymer.

[0008] Optionally, the perfluorosulfonic acid fluorine type resin is obtained by copolymerization of tetrafluoroethylene and the following monomers:

[0009]

[0010] wherein m=0-3 (preferably m=1-3), n≥2 (preferably 2 or 3), and X=SO2F.

[0011] Optionally, the perfluorosulfonic acid fluorine type resin is a long-chain branched perfluorosulfonic acid resin, and the number average molecular weight is 100-300 thousand.

[0012] The application further provides a preparation method of the composite reinforced perfluorosulfonic acid ion exchange membrane, which comprises the following steps: (1) mixing materials comprising perfluorosulfonic acid fluorine type resin, sulfonated graphene and additives in a proportion in a stirrer, extruding and granulating by a vented twin-screw extruder, cooling, and drying to obtain a master batch; the mass ratio of the perfluorosulfonic acid fluorine type resin, the sulfonated graphene and the 2,5-diamino-p-benzenedisulfonic acid is 100:5-8:1-3; (2) melt extruding the master batch by a single-screw extruder, directly casting the melt resin on the surface of a reinforcing mesh by a clothes hanger type vertical casting head with a gap of 1 mm, and preparing a perfluorosulfonic acid membrane through compression and cooling by a horizontal three-roll compression machine; and (3) treating the perfluorosulfonic acid membrane through sodium or hydrogen treatment to obtain a sodium type or hydrogen type composite reinforced perfluorosulfonic acid ion exchange membrane.

[0013] Optionally, the hydrogen treatment step is as follows: immersing the perfluorosulfonic acid membrane in a hydrochloric acid solution with a concentration of 5%-30% at a temperature of 80-90 ℃ for 5-7 h, washing with deionized water until neutral, and drying to obtain a hydrogen type composite reinforced perfluorosulfonic acid ion exchange membrane.

[0014] Optionally, the sodium treatment step is: immersing the perfluorosulfonic acid membrane into a 10% to 30% sodium hydroxide solution at a temperature of 80-90 DEG C for 5-6 hours, washing with deionized water until neutral, and drying, to convert the perfluorosulfonic acid ion exchange membrane into a sodium type composite reinforced perfluorosulfonic acid ion exchange membrane.

[0015] The application also provides a use of the composite reinforced perfluorosulfonic acid ion exchange membrane as described above, which is applied to fuel cells, lithium batteries, vanadium batteries, chlor-alkali electrolysis, gas separation, and photocatalysis.

[0016] The application has the following advantages:

[0017] 1. The perfluorosulfonic acid fluororesin is melted into a liquid state at high temperature without using a solvent, thereby solving the problems of human body damage and environmental pollution caused by solvent volatilization.

[0018] 2. The perfluorosulfonic acid fluororesin is modified by using a modifier such as sulfonated graphene and 2,5-diamino-p-benzenedisulfonic acid, which can ensure that the perfluorosulfonic acid fluororesin maintains stable fluidity during high-temperature processing, weakens non-Newtonian fluid properties, and stabilizes the melt flow rate (MFR) between 3.5 and 4 by controlling the addition amount of the modifier, so that the melt strength is appropriate, the extrusion casting film forming property is good, and the modified reinforced mesh cloth is easily compounded.

[0019] 3. The modified perfluorosulfonic acid fluororesin is compounded with the reinforced mesh cloth treated by plasma in a molten and plasticized state by a single-screw extruder, and becomes a film product after three-roller calendering and cooling by a horizontal three-roller calender, or is directly made into a cloth-based composite material by compounding with a base material through a three-roller calendering machine, which has good interlayer adhesion, good appearance flatness, and improved comprehensive mechanical properties.

[0020] 4. The modified resin and the reinforced mesh cloth are suitable for processing, have low requirements for equipment, and have good productivity. DETAILED DESCRIPTION

[0021] To make the above objectives, features and advantages of the application more apparent and comprehensible, the specific embodiments of the application are described in detail below.

[0022] In the following description, a lot of specific details are set forth in order to provide a thorough understanding of the application, but the application can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the concept of the application, so the application is not limited to the specific embodiments disclosed below.

[0023] The composite reinforced perfluorosulfonic acid ion exchange membrane according to the present application is obtained by melt extrusion and casting perfluorosulfonic acid resin modified material onto the surface of a modified reinforcing mesh and by compression bonding, and then by sodium or hydrogen treatment; the perfluorosulfonic acid resin modified material comprises perfluorosulfonic acid fluorine type resin, sulfonated graphene and 2,5-diamino-p-benzenedisulfonic acid, and the mass ratio of the perfluorosulfonic acid fluorine type resin, sulfonated graphene and 2,5-diamino-p-benzenedisulfonic acid is 100:5-8:0.8-2.

[0024] In an embodiment, the modified reinforcing mesh is a reinforcing mesh after plasma treatment.

[0025] In an embodiment, the material of the reinforcing mesh is one of polytetrafluoroethylene, polyvinylidene fluoride and ethylene-tetrafluoroethylene copolymer.

[0026] In an embodiment, the perfluorosulfonic acid fluorine type resin is obtained by copolymerization of tetrafluoroethylene and the following monomers:

[0027]

[0028] wherein m=0-3 (preferably m=1-3), n≥2 (preferably 2 or 3), and X=SO2F.

[0029] In an embodiment, the perfluorosulfonic acid fluorine type resin is a long-chain branched perfluorosulfonic acid resin with a number average molecular weight of 100-300 thousand.

[0030] The present application also provides a preparation method of the composite reinforced perfluorosulfonic acid ion exchange membrane as described above, comprising the following steps: (1) mixing the material comprising perfluorosulfonic acid fluorine type resin, sulfonated graphene and auxiliary agents in a proportion in a blender, extruding and granulating by a vented twin-screw extruder, cooling, drying to obtain a master batch; the mass ratio of the perfluorosulfonic acid fluorine type resin, sulfonated graphene and 2,5-diamino-p-benzenedisulfonic acid is 100:5-8:1-3; (2) melt extruding the master batch by a single-screw extruder, directly casting the melt resin onto the surface of the reinforcing mesh by a clothes hanger type vertical casting head with a gap of 1 mm, and then preparing a perfluorosulfonic acid membrane by compression bonding and cooling in a horizontal three-roll compression bonding machine; (3) treating the perfluorosulfonic acid membrane by sodium or hydrogen treatment to obtain a sodium type or hydrogen type composite reinforced perfluorosulfonic acid ion exchange membrane, respectively.

[0031] In the preparation method of the composite reinforced perfluorosulfonic acid ion exchange membrane according to the present application, the hydrogen treatment step can be: immersing the perfluorosulfonic acid membrane into a hydrochloric acid solution with a concentration of 5%-30% at a temperature of 80-90℃ for 5-7h, washing with deionized water until neutral, and then drying to convert into a hydrogen type composite reinforced perfluorosulfonic acid ion exchange membrane.

[0032] In the preparation method of the composite reinforced perfluorosulfonic acid ion exchange membrane according to the application, the sodium treatment step can be: immersing the perfluorosulfonic acid membrane into a sodium hydroxide solution with a concentration of 10% to 30%, at a temperature of 80-90°C, for 5-6 hours, washing with deionized water until neutral, and drying to obtain the composite reinforced perfluorosulfonic acid ion exchange membrane in sodium form.

[0033] The composite reinforced perfluorosulfonic acid ion exchange membrane according to the application can be applied to fuel cells, lithium batteries, vanadium batteries, chlor-alkali electrolysis, gas separation, and photocatalysis.

[0034] Example 1

[0035] (1) Perfluorosulfonic acid fluorine type resin with a molecular weight of about 100000, sulfonated graphene, and 2,5-diamino-p-benzenedisulfonic acid were thoroughly mixed and fed into an exhaust type double screw extruder with a screw diameter of 20 and a length-diameter ratio of 40, which was made of corrosion-resistant nickel-based alloy steel material, through a metering feeder for melt extrusion granulation, cooling, and drying to obtain a master batch; wherein the exhaust hole of the exhaust type double screw extruder was connected to a vacuum pump, and the vacuum degree was 0.1 MPa; the temperature of each section of the exhaust type double screw extruder was 280-320°C, and the temperature of the head was 290°C. The mass ratio of the perfluorosulfonic acid fluorine type resin, the sulfonated graphene, and the 2,5-diamino-p-benzenedisulfonic acid was 100:8:2.

[0036] (2) The master batch was melt extruded by a single screw extruder, and the melt resin was directly cast onto the surface of the reinforcing mesh cloth through a clothes hanger type vertical casting head with a slit gap of 1 mm, and then the perfluorosulfonic acid membrane was prepared after calendering and cooling by a horizontal three-roll calender; the temperature of each section of the single screw extruder was 280-315°C, and the temperature of the head was 320°C; the roller temperature of the horizontal three-roll calender was 40°C.

[0037] (3) The perfluorosulfonic acid membrane was immersed in a hydrochloric acid solution with a concentration of 5% at a temperature of 80°C for 5 hours, washed with deionized water until neutral, and dried to obtain the composite reinforced perfluorosulfonic acid ion exchange membrane in hydrogen form.

[0038] Example 2

[0039] (1) Perfluorosulfonic acid fluorine type resin with a molecular weight of about 300000, sulfonated graphene, and 2,5-diamino-p-benzenedisulfonic acid were thoroughly mixed and fed into an exhaust type double screw extruder with a screw diameter of 20 and a length-diameter ratio of 40, which was made of corrosion-resistant nickel-based alloy steel material, through a metering feeder for melt extrusion granulation, cooling, and drying to obtain a master batch; wherein the exhaust hole of the exhaust type double screw extruder was connected to a vacuum pump, and the vacuum degree was 0.5 MPa; the temperature of each section of the exhaust type double screw extruder was 295-340°C, and the temperature of the head was 310°C. The mass ratio of the perfluorosulfonic acid fluorine type resin, the sulfonated graphene, and the 2,5-diamino-p-benzenedisulfonic acid was 100:5:0.8.

[0040] (2) The master batch is melt-extruded by a single screw extruder, and the melt resin is directly cast onto the surface of the reinforcing mesh cloth through a clothes hanger type vertical casting head with a slit gap of 1 mm. After cooling and calendering by a horizontal three-roll calender, a perfluorosulfonic acid membrane is prepared. The temperature of each section of the single screw extruder is 295-330°C, and the temperature of the head is 330°C. The roller temperature of the horizontal three-roll calender is 60°C.

[0041] (3) The perfluorosulfonic acid membrane is immersed in a hydrochloric acid solution with a concentration of 30% at a temperature of 80-90°C for 7 h. After washing with deionized water until neutral and drying, the perfluorosulfonic acid membrane is converted into a hydrogen type composite reinforced perfluorosulfonic acid ion exchange membrane.

[0042] Example 3

[0043] (1) The perfluorosulfonic acid fluorine type resin with a molecular weight of about 134180, sulfonated graphene, and 2,5-diamino-p-benzenedisulfonic acid are thoroughly mixed and added to an exhaust type double screw extruder made of corrosion-resistant nickel-based alloy steel material with a screw diameter of 20 and a length-diameter ratio of 40 through a metering feeder for melt-extrusion granulation, cooling, and drying to obtain a master batch. The exhaust hole of the exhaust type double screw extruder is connected to a vacuum pump, and the vacuum degree is 0.4 MPa. The temperature of each section of the exhaust type double screw extruder is 292-328°C, and the temperature of the head is 305°C. The mass ratio of the perfluorosulfonic acid fluorine type resin, sulfonated graphene, and 2,5-diamino-p-benzenedisulfonic acid is 100:6:1.

[0044] (2) The master batch is melt-extruded by a single screw extruder, and the melt resin is directly cast onto the surface of the reinforcing mesh cloth through a clothes hanger type vertical casting head with a slit gap of 1 mm. After cooling and calendering by a horizontal three-roll calender, a perfluorosulfonic acid membrane is prepared. The temperature of each section of the single screw extruder is 280-320°C, and the temperature of the head is 320°C. The roller temperature of the horizontal three-roll calender is 50°C.

[0045] (3) The perfluorosulfonic acid membrane is immersed in a hydrochloric acid solution with a concentration of 20% at a temperature of 85°C for 6 h. After washing with deionized water until neutral and drying, the perfluorosulfonic acid membrane is converted into a hydrogen type composite reinforced perfluorosulfonic acid ion exchange membrane.

[0046] Example 4

[0047] Except for the replacement of hydrogen by sodium, the other steps are the same as in Example 3. The specific sodium treatment steps are as follows: the perfluorosulfonic acid membrane is immersed in a sodium hydroxide solution with a concentration of 25% at a temperature of 85°C for 5.5 h. After washing with deionized water until neutral and drying, the perfluorosulfonic acid membrane is converted into a sodium type composite reinforced perfluorosulfonic acid ion exchange membrane.

[0048] Comparative Example 1

[0049] Except that no sulfonated graphene and 2,5-diamino-p-benzenedisulfonic acid are added, other conditions are the same as those in Example 3.

[0050] Comparative Example 2

[0051] Except that no 2,5-diamino-p-benzenedisulfonic acid is added, other conditions are the same as those in Example 3.

[0052] Performance test

[0053] The thickness, mechanical strength and conductivity of the ion exchange membranes of the examples and comparative examples after saponification and acidification treatment were tested, and the specific data are shown in Table 1 below.

[0054] Table 1

[0055]

[0056] As can be seen from the data of the examples and comparative examples, the perfluorosulfonic acid fluororesin is modified by using the modifiers such as sulfonated graphene and 2,5-diamino-p-benzenedisulfonic acid, which can ensure that the perfluorosulfonic acid fluororesin maintains stable extrusion casting film-forming property during high-temperature processing, is easy to be compounded with the reinforced mesh after modification, has good interlayer adhesion, good dimensional stability, and improved comprehensive mechanical properties, and the hydrogenated or sodiumized perfluorosulfonic acid ion exchange membrane has good conductivity and good practicability.

[0057] The above examples are merely examples for clearly illustrating the present application, and are not intended to limit the embodiments. Based on the above description, other different forms of changes or modifications can be made by those skilled in the art. All the embodiments do not need to be exhausted, and the obvious changes or modifications derived therefrom are still within the protection scope of the present application.

Claims

1. A composite reinforced perfluorosulfonic acid ion exchange membrane, characterized by, The perfluorosulfonic acid membrane is obtained by melt extrusion and casting perfluorosulfonic acid resin modified material on the surface of a modified reinforcing mesh and by calendering compounding, wherein the perfluorosulfonic acid resin modified material comprises perfluorosulfonic acid fluorine type resin, sulfonated graphene and 2,5-diamino-p-benzenedisulfonic acid, and the mass ratio of the perfluorosulfonic acid fluorine type resin, the sulfonated graphene and the 2,5-diamino-p-benzenedisulfonic acid is 100:5-8:0.8-2; the modified reinforcing mesh is a reinforcing mesh after plasma treatment; and the material of the reinforcing mesh is one of polytetrafluoroethylene, polyvinylidene fluoride and ethylene-tetrafluoroethylene copolymer. The modified reinforcing mesh is a reinforcing mesh after plasma treatment. The material of the reinforcing mesh is one of polytetrafluoroethylene, polyvinylidene fluoride and ethylene-tetrafluoroethylene copolymer.

2. The composite reinforced perfluorosulfonic acid ion exchange membrane according to claim 1, wherein The perfluorosulfonic acid fluorine type resin is obtained by copolymerization of tetrafluoroethylene and the following monomers: wherein m=0-3, n≥2, and X=SO2F.

3. The composite reinforced perfluorosulfonic acid ion exchange membrane according to claim 1, wherein The perfluorosulfonic acid fluorine type resin is long-chain branched perfluorosulfonic acid resin with a number average molecular weight of 100-300 thousand.

4. The preparation method of the composite reinforced perfluorosulfonic acid ion exchange membrane according to any one of claims 1 to 3, characterized in that, The method comprises the following steps: (1) The material comprising perfluorosulfonic acid fluorine type resin, sulfonated graphene and auxiliary agents is mixed in a proportion in a blender, extruded and granulated by a vented twin-screw extruder, cooled, and dried to obtain a master batch, wherein the mass ratio of the perfluorosulfonic acid fluorine type resin, the sulfonated graphene and the 2,5-diamino-p-benzenedisulfonic acid is 100:5-8:1-3; (2) The master batch is melt extruded by a single-screw extruder, directly cast onto the surface of the reinforcing mesh by a clothes hanger type vertical casting die head with a gap of 1mm, and then calendered and cooled by a horizontal three-roll calender to obtain the perfluorosulfonic acid membrane; (3) The perfluorosulfonic acid membrane is treated by sodiumization or hydrogenation to obtain a sodium type or hydrogen type composite reinforced perfluorosulfonic acid ion exchange membrane, respectively.

5. The preparation method of the composite reinforced perfluorosulfonic acid ion exchange membrane according to claim 4, characterized in that, The hydrogenation treatment step is as follows: the perfluorosulfonic acid membrane is immersed in a hydrochloric acid solution with a concentration of 5%-30% at a temperature of 80-90℃ for 5-7h, washed with deionized water until neutral, and then dried to obtain a hydrogen type composite reinforced perfluorosulfonic acid ion exchange membrane.

6. The method for preparing a composite reinforced perfluorosulfonic acid ion exchange membrane according to claim 4, characterized by, The sodiumization treatment step is as follows: the perfluorosulfonic acid membrane is immersed in a sodium hydroxide solution with a concentration of 10%-30% at a temperature of 80-90℃ for 5-6h, washed with deionized water until neutral, and then dried to obtain a sodium type composite reinforced perfluorosulfonic acid ion exchange membrane.

7. Use of the composite reinforced perfluorosulfonic acid ion exchange membrane according to any one of claims 1 to 3 or the composite reinforced perfluorosulfonic acid ion exchange membrane produced by the method according to any one of claims 4 to 6, characterized in that, The composite reinforced perfluorosulfonic acid ion exchange membrane is applied to fuel cells, lithium batteries, vanadium batteries, chlor-alkali electrolysis, gas separation and photocatalysis.

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